Performance Degradation on 0.10.0-preview2

After upgrading a project which uses AvaloniaEdit from 0.9.0 to 0.10.0-preview2 things are working, well, 10 times slower. Using Ubuntu 18.04 LTS KDE, the following markup is used to instantiate and draw the editor:

<avaloniaEdit:TextEditor
    FontFamily="Ubuntu Mono"
    x:Name="AvaloniaEdit"
    HorizontalAlignment="Stretch"
    VerticalAlignment="Stretch"
    HorizontalScrollBarVisibility="Auto"
    VerticalScrollBarVisibility="Auto">
    <avaloniaEdit:TextEditor.Options>
        <avaloniaEdit:TextEditorOptions 
            ConvertTabsToSpaces="True"
            IndentationSize="4"
            ShowTabs="True" />
    </avaloniaEdit:TextEditor.Options>
</avaloniaEdit:TextEditor>

This is how it was working with 0.9.* (absolutely fast):

This is how it works after the upgrade to 0.10.0-preview* (almost a slideshow):

The following xml file represents the highlighting: https://gist.github.com/worldbeater/9f85062caddeceb8cf97719c306546e4

dotnet --info
.NET Core SDK (reflecting any global.json):
 Version:   3.1.100
 Commit:    cd82f021f4

Runtime Environment:
 OS Name:     ubuntu
 OS Version:  18.04
 OS Platform: Linux
 RID:         ubuntu.18.04-x64
 Base Path:   /usr/share/dotnet/sdk/3.1.100/

Host (useful for support):
  Version: 3.1.0
  Commit:  157910edee

.NET Core SDKs installed:
  2.1.802 [/usr/share/dotnet/sdk]
  2.2.402 [/usr/share/dotnet/sdk]
  3.1.100 [/usr/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.14 [/usr/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.8 [/usr/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.14 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.8 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.0 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.14 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.8 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.0 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

Ping me if any further details are required.

[Gillibald]

That issue is unrelated. Totally different text rendering stack.

[worldbeater]

@aelij just verified with AvaloniaEdit added as a submodule, and can confirm that https://github.com/AvaloniaUI/AvaloniaEdit/pull/110 really fixes the issue on Linux!